HLS has a number of meanings:
- Harvard Law School
- High-level synthesis
- Historisches Lexikon der Schweiz, a Swiss encyclopedia.
- Hue, Saturation, Lightness color space (can be referred to as either HLS or HSL)
- Huntingdon Life Sciences, a contract animal-testing company based in Huntingdon, England, and New Jersey.
- Highlands Latin School, a Classical Christian School in Louisville, Kentucky
- HTTP Live Streaming, a multimedia streaming technology